Default Problem with 64gig Samsung class 10 sdcard

I am using a Samsung Class 10 64gig sdcard and it has been working well but all of a sudden even though it shows as 58gig on the phone it only shows as 236kb on the pc when using it through a card reader.

I have tried to format using guiformat, SDFormatterv4 & HP USB Disk Storage Format Tool and nothing works.

The only thing different I have done is use SDCard Fixer due to a problem using Ditto Rom.

Any help appreciated